1. Field of the Invention
The invention concerns a method for continuously mixing and degassing liquid, castable media, in particular components of casting resins and, where called for, fillers such as quartz dust, aluminum oxide or dyes, using a continuous degassing apparatus as well as equipment for carrying out the method.
2. Description of the Prior Art
An apparatus and a procedure for continuously degassing casting resin is known from the German patent document 42 22 695 A1. During the resin casting, the resins or hardeners may have to be mixed with fillers such as quartz dust, Mikrodol (ground dolomite), aluminum oxide and the like, or with further substances such as dyes, and must be degassed under vacuum in order that the products made from such casting-resin formulations, for instance electrically insulating parts, be endowed with the required properties. Whereas the mixtures of the resin/filler or hardener/filler are prepared in so-called formulating operations, and then are delivered to the end processor, other end consumers carry out such formulations of the mixtures of resin/filler or hardener/filler themselves. Typically such operations are carried out batch-wise.
When the end processor implements the formulation, the components as a rule also are degassed, and consequently, material is available batch-wise for processing. If such material is delivered from a formulation operation, it requires being set to the proper temperature and be degassed before being processed. Such a procedure entails uneconomical work stoppages if the consumption of one batch is followed by a wait for a subsequent batch. Therefore, the typical procedure calls for such charges being sufficient for one or two work shifts a day and that replenishment, or new metering and mixing, be carried out in the time remaining, preferably at night. As a result the supply containers and mixers must be commensurately large. If, on the other hand, casting material must be available around the clock, then all batch mixers must be kept ready. These batch mixers are present upstream in front of the supply containers from which the material will then be processed. Besides the corresponding expense in construction, the supplies of material must wait for substantial durations, sometimes hours, prior to procvessing. Moreover, there are significant initial delays until processing starts. Again such batch mixers, even when designed as so-called thin-layer degassing mixers, require comparatively long mixture degassing-times because the better degassed mixture flowing back from the discharge cone into the batch is constantly being mixed with the batch as yet not optimally degassed. Illustratively, such a thin-layer degassing mixer is known from the German patent document 30 26 429 A1.
In the light of the above state of the art, it is the object of the invention to create a method, and implementing equipment as initially defined above, making continuously available components of casting resin in homogeneous and degassed form for further processing. The present invention requires less expensive construction and, as compared to the total amount of material present in the facility, being operative with small and already pre-formulated amounts of material.